Magnetic Properties of Pr–Fe–Al Alloys Produced by the Metallic Mold Casting Method

Abstract

The structures and magnetic properties of Pr-Fe-Al alloys produced by the metallic mold casting method were investigated. The Pr-Fe-Al alloy consisted of the amorphous phase together with the non-ferromagnetic Pr phase. Magnetic measurements confirmed that the origin of coercivity in the alloys was the amorphous phase. It was found that the Curie temperature and coercivity of the alloys were strongly dependent on the composition of the amorphous phase.

Magnetic and anomalous magnetic viscosity in the bulk amorphous ferromagnet and partially amorphous ferromagnet

“…1(a) and it can be seen that there are diffuse broad Bragg peaks centered around 2y values of 301 and 551, which is consistent with a structural coherence length of o5 nm [13]. Saito [12] has undertaken a study of the Pr-Fe-Al phase diagram, and reports a similar XRD pattern for a Pr-Fe-Al bulk amorphous alloy, as does [13] for bulk amorphous Nd-Fe-Al. It has been pointed out by McCallum et al [13] that laboratory XRD lacks resolution for revealing fine structural detail, that may have a nanometre length scale.…”

“…When compared to the partially amorphous alloy, the amorphous alloy, with its higher Al content, exhibits a higher remanence and lower intrinsic coercivity. The decrease in coercivity with increasing Al content has also been noted in [12]. Coercivity is an extrinsic property, and materials that display a high coercivity, such as 'pinned' type magnets, have a microstructure (defects, grain boundaries, crystal like inclusions, etc.)…”

“…More recently anomalous magnetic viscosity has been observed in the bulk amorphous ferromagnets Nd 60 Fe 30 Al 10 [6,7] and Nd 60 Fe 20 Co 10 Al 10 [8]. The advent of bulk metallic glasses (BMG) or bulk amorphous alloys [9], particulary (Nd,Pr)-Fe-Al alloys which possess hard magnetic properties (termed bulk amorphous ferromagnets), has resulted in a material that seems to be ideal for studying time-dependent magnetic effects [10][11][12][13]. Unlike glassy metal ribbons which are only a few microns in thickness, and require cooling rates of 10 6 K=s, bulk amorphous alloys form at much more modest cooling rates, typically a few tens K/s, and can be cast into rods some millimetres or even centimetres in diameter [14].…”

Temperature dependence of the coercivity in Nd60Fe30−xCoxAl10, x=0 or 10, and Pr58Fe24Al18 bulk amorphous ferromagnets

“…Unlike their glassy-metal relations, that require cooling rates of 10 6 K/s, they form at more modest cooling rates of a few tens or hundreds of K/s, resulting in specimens that may be many millimetres in diameter [4]. Some bulk amorphous alloys, of specific composition, based on RE-FeAl, RE=Nd or Pr, display hard magnetic properties, typically having a coercivity of 200-300 kA/m, and these are known as bulk amorphous ferromagnets [5][6][7].…”

Undercooling Solidification and Magnetic Properties of Pr<SUB>90</SUB>Fe<SUB>10</SUB> Alloy Produced by the Gas Flow Levitation Method

“…2,3) Rare-earth-based alloys have been investigated due to their unique magnetic properties, complex crystallization behavior, and high amorphous forming ability. [5][6][7][8][9][10][11][12] In particular, the magnetic properties and microstructure of Nd-Fe based alloys have been studied due to their complex microstructure, good magnetic properties, and relation to the Nd-Fe-B permanent magnets by many researchers. Nd-Fe and Pr-Fe amorphous ribbons displayed hard magnetic properties at low temperatures.…”